Even while MGT gear up for releasing the SAM Coupe (see News) they continue to support the Spectrum with new products. Two of the most interesting are the Fixer and the TwoFace. While the former has proved unexpectedly popular, the latter has proved over-ambitious and is unlikely to be continued in production.

The Fixer is a small circuit board and edge connector designed to allow owners of the +2A to use the MGT Plus D disk interface. Regular readers will know the + 2A is the black cased version of a +2 with a +3 circuit-board inside. Since the +3 has a redesigned edge connector many interfaces are incompatible with it. MGT have subsequently been surprised by the interest in this gadget, with people hoping it will solve problems with other interfaces as well. Apparently some high street stores are even talking about stocking it.

The Fixer comes in two basic versions, both costing £9.05. A standard version will connect the +2A to the Plus D, while another version allows the Opus Discovery disk drive to work with the +2A. Obviously the Fixer only solves interface problems, and games which crash due to +3 changes in the ROM chips will be unaffected by the Fixer.

To see how well the standard Fixer works I connected to my +3 and gave it a whirl. In 48 Basic it runs almost every interface I connected to it. The ZX Interface One and microdrive combination worked perfectly (thought trying to select +3 Basic crashed the Spectrum immediately). The SwiftDisc II interface (reviewed next month) also worked fine in 48 Basic, but was also usable after the SPECTRUM command was entered from +3 Basic (ie 'quasi-48 Basic'), This gives the advantage that the extra memory is still accessible to machine code. Multiface 1 and 128 both run on the +3 via the Fixer- in 48 Basic or the quasi mode, with Multiface 3 running too! This meant that I was able to run Genie on my +3 at last - loading games using Multiface 3, set up to put the machine into 48 Basic after the load, then using Multiface 128 to run Genie 128.

Using what the Fixer is designed for, I had similar results. The Plus D interface worked fine in 48 Basic or quasi-48 Basic, but would not run under +3 Basic. The interface will, curiously, boot from +3 Basic (by typing RUN) but crashes when booting has finished.

Miles Gordon Technology tell me that the Plus D does work in 128 Basic on the +2A so the +3 disk system must be causing problems. I don't know how much Amstrad would charge for their add-on disk drive, assuming that they bring it to market, but my money would go on the MGT Plus D or Sixword Swiftdisc system (both much faster than the +3, and a lot more compatible with existing utility programs).

The MGT TwoFace is another add-on aimed mainly at Plus D users. It is reminiscent of the old Currah Micro-slot, in that it allows the Plus D (which has no expansion connector) to be used on the Spectrum along with other interfaces. It is more sophisticated however, in that a switch allows either device to be isolated, and there is also a built-in Kempston joystick interface.

When a Plus D is fitted to the TwoFace, it is mounted vertically, the combination extending some 6 inches above the desk (with the disk drive cable emerging from the top) - so anyone who has the Spectrum immediately in front of the TV may need to raise the screen so it can still be seen. A metal bracket (supplied with the TwoFace) allows the Plus D to be bolted rigidly to the TwoFace, so that there is no wobble.

The switch on the TwoFace allows the Plus D (in the top socket) to be active in the forward or centre position. The rear socket (at least, whatever is plugged into it) is active in the forward or rear position. The built-in Kempston joystick interface is always active (unless an internal wire link is cut, which does not void the guarantee).

Which interfaces work in the rear connector along with the Plus D interface is a problem to answer. Some devices won't work because they clash with the Plus D in such a way that even the disabling switch on the TwoFace cannot help. Others won't work because the Spectrum itself cannot drive both interfaces at one time (some Spectrums have an 'underpowered' edge connector and cannot drive more than one device at once).

Miles Gordon Technology suggest that the best method is to try the required combination of interfaces and TwoFace (there is a problem-solving flowchart with the TwoFace documentation). However, they advise that interfaces such as the ZX Interface One, Swiftdisc and Alphacom printer are unlikely to work. Interfaces like the Opus Discovery and Beta interface, and even a second Plus D, should work okay.

My own tests largely confirm MGT's advice. The Plus D and ZX interface One seem to be totally incompatible! The Six- word Swiftdisc II seems to run OK, provided that the Plus D is disabled using the switch. However, the Plus D is unable to operate usefully. My Alphacom printer and Plus D combination tended to work OK (most of the time) provided that the switch was correctly moved before each device was used - rather laborious, and it makes printing disk catalogues impossible! Trying the Rotronics Wafadrive and Plus D gave rather different results - the Plus D worked fine but the Wafadrive crashed as soon as it was initialised.

So, the TwoFace will mainly be of use to Opus Discovery or Beta interface owners wishing to upgrade to a Plus D system (it is a shame that it is not Interface One compatible to allow upgrades for those users), or for those Spectrum users simply needing the additional edge connector (for example, the non- Disciple Multiface 1 & Plus D work fine together via the TwoFace, provided that the switch is used to keep them separate). The other possible TwoFace purchaser is a Plus D owner needing a Kempston Joystick interface, since one is built in. At £29.95, the TwoFace would be an expensive joystick interface, but gives the option of adding other hardware to the Plus D at a later date. Remember that if the TwoFace does not work for you, MGT promise to refund the cost of the Plus D if it is returned undamaged.

RAGE HARD!

Phil South looks at the ultimate deterrent in the RAM pack wobble stakes, as MGT launches the TwoFace, a switchable two-way user port.

FAX BOX

Gear: MGT TwoFace
Price: £16.95
Supplier: Miles Gordon Technology, Lakeside, Phoenix Way, Swansea Enterprise Park, Swansea SA7 9EH

A what? A switchable interface for my user port? Why would I want one of those?" I said. MGT smiled at me and said, "Try it." Oh well, I'm game for a laugh, so I tried it. To my great surprise, I liked it, and found it more useful than many other things I've shoved into my user port. Fnar!

Expansion ports have been popular for years, allowing the industrious Speccy user to connect as many gadgets as he likes to his machine, all at once. But such ports have always been fraught with problems. In most cases they're just a piece of ribbon cable which has been soldered with a spare male connector in the centre. I've used a lot of these jury-rigged ribbon style connectors in my time, and they've always been wobbly, unreliable, and had a nasty tendency towards crashing. And the most perilous kinds of connection are those which involve the dreaded PRINTER INTERFACES!! How many times have you wanted to print something out from your Speccy and found that the port is gummed up with the very item you want to print from?

DR SNOUTY'S CASEBOOK

Take the VTX5000. A fine little modem, and very inexpensive to buy. But what do you do if you want to print out your screens of Prestel/Micronet? It seems like a fairly simple process. You save your screens to tape online, and print them out offline when the modem's detached from your user port. Or so you'd have thought. But in order to recall the screens from tape, you have to have the modem attached. Why? 'Cos the screens are in a special format, peculiar to Prestel, and won't load in a naked Spectrum.

Okay, so you wedge your printer interface into your user port, then the lead from the modem. But the modem sits under the Spectrum, raising the interface off the ground and makes it wobble. The computer crashes. So you get smart and lay your modem upside down. BEHIND the Spectrum, so everything's in contact with the table But it still doesn't work. You unplug everything, plug it back together... and so on.

This all sounds pretty stupid, but it often happens. A dodgy lead trashed my Speccy, and it was all down to the jolly old 56 way connectors which are the only way the Speccy can communicate with outside peripherals.

That's where the TwoFace comes in. You can connect your peripherals, like the Plus D disk interface, printer, Vidi ZX, whatever, to your ports, and either switch them in one at a time, or all together. This is an excellent idea from my point of view, as not only will it allow me hours of trouble-free computing, it'll stop me drop-kicking the little fiend through the window! Anyroad, before I get carried away, let me tell you all about the physical construct ton of the device.

SO, WHAT'S IN IT?

The construction of the device is very neat. No floating circuit boards, no messy wires whizzing around all over the shop, just neat and tidy little ICs nestling on a few solidly fixed Printed Circuit Boards (PCBs).

The chips are what you'd expect from a device of this type, especially one with a Kempston compatible joystick port wedged on the side. On the secondary PCB are the three chips. A 74LS240 Octal Buffer, a 74LS32 Quad 2-Input OR Gate, and a 74LS138 3-Line to 8-Line Decoder. These chips do two jobs. Firstly they wire in a joystick into the user port, and secondly, they make sure that you can switch the IORQ and MREQ pins" without causing any hardware headaches.

The only other bits inside the box are a 9-way right angle male D Connector (joystick port to you) a 4-pole 3-position slide switch, and the three PCBs, including 2 x male and 1 x female 54-way connectors and a metal casing. Four rubber feet on the bottom of the unit keep it at the same level as the user port on the Spectrum. The unit rests very comfortably behind the Spectrum, and is as sturdy and wobble-free a unit as I've ever lobbed onto my user port. It's stability comes from the metal casing, plus its grippy rubber feet, which hold the surface of the table so well, that for a minute I thought it was stuck to it!

YES, BUT WHAT'S IT LIKE!

The TwoFace works well. The select switch on the top means you can have either both ports in use at once, just the back one, or just the front one. And the best thing about the TwoFace is that because it's only switching the IO and Memory Request lines, you can usually fit incompatible interfaces to it with absolutely no hassle - no crashing and no chip rupture. And even if they are incompatible, you have the choice to switch them in or out to your own requirements.

Being able to use a Kempston joystick at any time is good news too, as most joystick ports are a bit tricky to use in conjunction with anything else. Another nice feature for +D users is the little gizmo that comes free with the TwoFace called a 'wobble plate'. Sounds like a serving of jelly to me, but in fact it's a small piece of metal which screws into the TwoFace, and also into the +0 m the upright position This means the two units are as one, and every time you press the snapshot button, you get a lovely picture of your screen, not a busted Spectrum. Yes folks, you can say bye to the wobble, then, I wonder if MGT do the same for my tummy…